Motor fuel



-' Patented June 20, 1950 MOTOR FUEL Charles B. Biswell, Woodstown, and George Alvin Sayers, Penns Grove, N. J., assignors to E. I. du Pont de Nemours 8: Company, Wilmington, Del., a corporation of Delaware No Drawing This invention relates to motor fuels and particularly to aviation motor fuels containing tetraethyl lead, ethylenedibromide and N,N'-di(secondary butyl)-p-phenylenediamine.

It has been found that N,N'-di(secondary butyl)-p-phenylenediamine is very effective to inhibit gum formation in cracked gasoline and to inhibit deterioration of tetraethyl lead added, or to be added, to motor-fuels. When tetraethyl lead is added to a motor fuel, it is accompanied by at least an equimolecular amount of an organic halogen compound as a lead scavenger.

In aviation motor fuels containing tetraethyl lead, the organic halogen compound is solely ethylenedibromide and is present in the proportion of substantially one mol for each mol of the tetraethyl lead.

Normally N,N'-di(secondary butyl) -p-phenylenediamine is quite stable and, when employed in a motor fuel in the absence of'ethylenedibromide, it will, upon exposure to sunlight, slowly form a red product, apparently due to a photochemically induced oxidation, which color formation becomes objectionable in amount and intensity only after several days of exposure. Since, in practice, motor fuels are not subjected to such long exposures to sunlight and generally not more than 30 minutes, such color formation does not present a problem and there is no necessity for adding to the motor fuel any material to' prevent such color formation.

ill

When N,N'-di(secondary butyl) -p-pheny1enediamine is employed in an aviation motor fuel in a concentration of at least 0.0014% by weight and the fuel also contains ethylene dibromide, a

strong red colored product is formed rapidly upon alter the color of the motor fuel to an objection',

able extent in from a few seconds to 10 minutes. The color of such red product isso intense that even traces thereof seriously alter the color of the fuel. Such results are not altered by the substantially complete. elimination of oxygen, as by first sweeping the fuel with nitrogen and thereafter keeping it blanketed with nitrogen.

Application October 27, 1948,- Serial No. 56,922

. 17 Claims. (ous-e9)" It is thus apparent that the red product so formed is a different product formed by a different reaction or series of reactions than the prod- ,uct formed by the slow oxidation of N,N'-di(secondary butyl) -p-phenylenediamine in the absence of ethylenedibromide.

The formation of the red colored product, in motor fuels containing N,N'-di(secondary butyl) p-phenylenediamine and ethylenedibromide on exposure to sunlight,- is particularly serious in aviation fuels. Aviation fuels are composed substantially wholly of saturated hydrocarbons, such as straight-run gasoline, isooctane, neohexane, reformed gasoline, hydroformed gasoline, polymer gasoline, alkylate and blends of two or more thereof, and usually contain tetraethyl lead and ethylenedibromide as the sole lead scavenger. Aviation fuels are manufacture to have different octane numbers, usually 91, and octane, and each motor is specially designed to operate with a fuel of a particular octane number and will not operate properly with a fuel of a different octane number and particularly a lower octane number. Accordingly, aviation fuels of different octane numbers. are dyed different identifying colors, 91 octane fuel being dyed blue, 100 octane fuel being dyed green and 115 octane fuel being dyed purple. The formation or red products in such fuels changes their identifying colors; changing blue fuel to .purple, changing green fuel to gray and then purple, and making purple fuel very much redder. This has caused the erroneous identification of aviation fuels resulting in the loss of aviation motors and endangering human life.

It is an object of our invention to provide aviation fuels containing tetraethyl lead, ethylenedibromide, N,N'-di(secondary butyl)-p-phenylenediamine and an organic nitrogenous base to prevent rapid change in color of the aviation fuel upon exposure to sunlight. Another object is to discharge color formed in an aviation fuel, containing tetraethyl lead, ethylenedibromide and 'N,N'-di(secondary butyl) -p-phenylenediamine, upon exposure to sunlight. A further object is to prevent change in color of aviation motor fuels containing tetraethyl lead, ethylenedibromide and N,N'-di(secondary butyl)-pphenylenediamine. Other objects are to provide new compositions of matter and to advance the art. Still other objects will appear hereinafter.

The above and other objects may be accomplished in accordance with'o'ur invention which comprises adding to an aviation motor fuel, containing tetraethyl lead, ethylenedibromide and N,N'-di(secondary butyl )-p-phenylenediamine, from about 0.25 mol to about 3 mols of an organic nitrogenous base for each mol of N,N-di(secondary butyl)-p-phenylenediamine, the organic nitrogenous base being composed solely of carbon atoms, hydrogen atoms and at least one basic nitrogen atom, and said organic nitrogenous base having a dissociation constant of from about 2 10- to about l lboiling above 30 C. at atmospheric pressure and being free of multiple bonds other than those of a benzene ring. We have found that, when such amounts of such organic nitrogenous bases are added to such aviation fuels, they effectively prevent the formation of the intensely red products, ordinarily formed by such fuels upon exposure to sunlight, for the periods of time required for practical purposes and usually for about 30 minutes or more. Also, if the aviation fuel has become colored by exposure to sunlight before the organic nitrogenous base has been added thereto, the addition of an organic nitrogenous base of our invention will discharge such color and restore the original color of the fuel. In the later case, it will generally be desirable to add a larger amount of the organic nitrogenousbase, e. g., an amount sumcient to discharge the color plus an amount suincient to prevent further color change for the desired period.

Our invention is particularly adapted to the treatment of aviation fuels which are substantially saturated hydrocarbons, such as straight-run gasoline, iso-octane, neohexane, reformed gasoline, hydroformed gasoline, polymer gasoline, a1- kylat-e and blends of any two or more thereof.

The aviation fuel will contain from about 0.5 cc. to about 8 cc. of tetraethyl lead per gallon of fuel and, preferably, from about 2 cc. to about cc. per gallon. The ethylenedibromide will be present in the aviation fuel in the proportion of from about 0.22 cc. to about 3.6 cc. per gallon of fuel and, preferably, from about 0.9 cc. to about 2.25 cc. per gallon. The ethylenedibromidewill be the sole lead scavenger and will be present in an amount chemically equivalent to the tetraethyl lead.

The aviation fuel will contain N,N-di(secondary butyl) -p-phenylenediamine in the proportion of from about 0.0014% to about 0.008% by weight (from about 0.038 to about 0.218 gram per gallon of fuel) and, preferably, from about 0.0018% to about 0.004% by weight (from about 0.049 to about 0.109 gram per gallon of fuel). Generally, the amount of N,N'-di(secondary butyl) -pphenylenediamine employed will be dependent upon the amount of tetraethyl lead in the fuel, increasing with increasing amounts of tetraethyl lead, since the most important function of the N,N' -di (secondary butyl) -p-phenylenediamine is to prevent decomposition of the tetraethyl lead, generally indicated by the formation of a haze or a precipitate.

The organic nitrogenous bases which are to be used in accordance with our invention are those which have dissociation constants of from about 2 10- to about l l0-" and, preferably, those having dissociation constants of from about 2 10* to about 1 10- and are composed solely of carbon atoms, hydrogen atoms and one or more basic nitrogen atoms. Also, such organic nitrogenous bases should be free of multiple bonds other than those of a benzene ring; 1, e., except for the carbon atoms of a benzene ring, no two atoms should be bonded together by a double or a triple bond, such as C=C, C C, C==N and CEN. Also, in order to avoid danger of evaporation of the organic base from the fuel, the organic nitrogenous bases should be those which boll at temperatures above 30 C. at'atmospheric pressures. The organic nitrogenous bases include primary, secondary and tertiary amines and polyamines and the reduced heterocyclic nitrogen bases, such as piperidine. While the organic nitrogenous bases may contain aromatic groups, the preferred compounds are those which are aliphatic in character and are completely saturated, such as the alkyl amines, the alicyclic amines, the alkylene polyamines, and the reduced heterocyclic nitrogenous bases. Organic nitrogenous bases, which have been found to be highly effective for preventing the production of the intensely red product by ethylenedibromide and N,N-di(secondary butyl) -p-phenylenediamine in a motor fuel on exposure to sunlight, are listed below, together with the dissociation constants of representative members thereof:

Organic Bases J EEE PE,

Monoisopropylamine 4. 3X10- Mono-normal butylamine 4. 1X10- Monoseeondory butylamine 3. 0X10- Mono-isoamylamine 4. 0X10- Monomormal heptylamine Mono-normal octylamiu Mono dodecylamina 4. 3X 10- Mono stearylamiue. Diisopropylamiua Di-normal butylamine Di-normal amylamine Tri-normal butylamine. N,N-Dimeth vlcetylamine Cyciohexylnmine. Benzyiamine 1,2-cthylenediamine 1.2-propylenediamine Diethylen etriarnine. Tricthylcn etetramine 'ietraethylencpentamine Dipropylcnetriamincn Npbenylethylenedia nin e Tetrabutylethylc edr mm iperidine 1.6Xl0 Pvrrolidina Dipiperidyl Morpholine 2X10- Alpha-pipecoline 9 6x10 The amount of the organic nitrogenous base or bases employed will be dependent upon the amount of N,N'-di(secondary butyl) -p-phenylcnediamine, and will fall within the range of from about 0.25 mol to about 3 mols for each mol of the N,N-di(secondary butyl)-p-phenylenediamine and, preferably, from about 0.3 mol to about 2.5 mols. Since not all of the organic nitrog enous bases are equally effective, the amount employed will vary somewhat with the effectiveness of the organic nitrogenous base. Where the organic nitrogenous base contains a single basic nitrogen atom, it will be employed in the proportion of from about 0.5 mol to about 3 mols for each mol of N,N('-disec'ondary butyl) -p-phenylenediamine and, preferably, from about 0.6 mol to about 2.5 mols. Where the organic nitrogenous base contains a plurality of basic nitrogen atoms, it will be employed in the proportion of from about 0.25 mol to about 2 mols for each mol of N,N-di(secondary butyl)-p-phenylenediamine and, preferably, from about 0.3 mol to about 1.7 mols. Larger proportions of the organic nitrogenous bases may be used, but without advantage, and will generally be undesirable as constituting an unnecessary impurity in the fuel.

The organic nitrogenous bases may be added to the aviation fuel prior to the addition of the other ingredients, such as tetraethyl lead, ethylenedibromide and N,N'-di(secondary butyl) -pphenylenediamlne, simultaneously with the addition .of any one or more of such ingredients, or subsequently to the addition of such ingredients. They may even be added after the intensely red colored product has been formed in the fuel formation of the red product, when incorporated in fuel containing N,N'-di(secondary butyl) -pphenylenediamine and ethylenedibromide with subsequent exposure of the motor fuel to sunlight. When such salt is added to motor fuel containing N,N'-di(secondary butyl)-p-phenylenediamine but no ethylenedibromide and the fuel is exposed to sunlight, the red product is formed in a few minutes but at a slower rate than a when uncom-bined ethylenedibromlde is present. Accordingly, it is necessary to add the organic nitrogenous bases to the motor fuel independently of the ethylenedibromide.

The organic nitrogenous bases must be used as such. Their salts are inoperable as will appear from the preceding paragraph and the following experiment. A motor fuel, containing N,N'-di- (secondary butyl)-p-phenylenediamine, ethylenedibromideand an organic nitrogenous baseof our invention, was exposed to sunlight for a period suflicient to produce an intense red color in the absence of the organic nitrogenous base. Thereafter, acids, e. g., acetic acid and hydrobromic acid, wereadded to samples of the motor fuel in an amount sufficient to neutralize the organic nitrogenous base, whereupon the intense red color was produced instantly.

Q minutes for the color to change from blue to purple are shown in the followingTable I:

Table I Per Cent Mel Ame Cone. Ratio Time Nnne 2 lsopropylamine 0. 0000 0. 626 30 Do 0. 001 l. 037 90 n-Butylamine 0. 0005 0. 420 7 Do 0. 0000 0. 504 80 0. 001 0. 843 90 sec-Butylamlne 0. 0005 0. 420 0 o 0. 0006 0. 504 ll 0. 001 0. 843 90 Isoamylamin 0. 0005 0. 352 0 0. 0006 0. 423 20 Do 0.001 0. 704 90 Cyclohexylamln e. 0. 0005 0. 309 8 Do 0. 0007 0. 434 18 Do 0.001 0.618 00 Triethylenetetramma. 0. 0005 0. 210 12 Do. -1 0. 0000, 0. 251 50 Do. 0. 0007 0. 294 60 Do. 0. 001 0. 419 90 Piperidine 0. 0005 0. 360 10 Do--- 0. 0007 0. 504 -25 Do u 0. 001 0. 722 90 EXAMPLE 2 of the same fuel were placed in direct sunlight. I

The untreated sample became dark gray in color within 5 minutes, and developed a distinct purple color-within 10 minutes. The green color of the treated sample had not changed after minutes of exposure.

EXAMPLE 3 A sample of 115 octane, aviation fuel (containing a purple dye, 2 cc. tetraethyl'lead, 0.9 cc.

. In order to more clearly illustrate our inven- 1 tion, preferred modes of carrying the same into effect and advantageous results to be obtained thereby, the following examples are given:

EXAMPLEII Samples of an aviation fuel (containing 2 milliliters of tetraethyl lead, 0.9 milliliter of ethylenedibromide, 0.0075 gram of a blue gasoline dye and 0.098 gram of N,N'-di(secondary butyl)-pphenylenediamine per gallon of fuel) were placed in clear glass sample bottles, 100 cc. fuel to each minutes, whereas the samples, to which the organic nitrogenous bases were added, were much more resistant to color change. The organic nitrogenous bases employed, their concentrations in the fuel, the mol ratio (mols of organic nitrogenous base to each mol of N,N'-di(secondary butyl)-p-phenylenediamine), and the time in bottles.

ethylenedibromide, and 0.098 gram N,N-di(secondary butyl) -p-phenylenediamine per gallon of fuel) was exposed to direct sunlight simultaneously with a sample of the same fuel to which had been added 0.0006% by weight of dipropylenetriamine (about 16.7% by weight of dipropylenetriamine based on the N,N-di(secondary butyl) p-phenylenediamine and a mol ratio of 0.314 to After 5 minutes exposure, the untreated sample-of fuel had become very much redder in color. The sample, containing the dipropylenetriamine, had not changed even after 45 minutes of exposure.

EXALEPLE4 One gallon of iso-octane (containing 2 cc. tetraethyl lead, 0.9 cc. ethylenedibromide and 0.098 gram of N,N-di(secondary butyl)-pphenylenediamine) was divided into cc. portions which were placed in clear glass sample Some of these portions were treated with 0.001% by weight of organic nitrogenous bases (about 27.8% by weight based on the N,N'- di(secondary butyl) p -'phenylenediamine).

These treated samples were then placed in direct sunlight along with a control sample of the fuel to which no organic nitrogenous base had been added. The control sample turned distinctly pink within 10 seconds. None of the treated samples showed any color change after 60 minutes exposure. The organic nitrogenous bases and the mols thereof for each mol of N,N'-

di(secondary butyl) p -phenylenediamine are shown in the following Table II:

2 Table II Base Mols Mono-n-heptylaminc Mononpctylamine Pyrrolidine DipiperidyL Morpholine..; l,2-Propylenediamine l ,2-E tbylenediamina Diethylene triamine. 'letraethylene pentamine EXALIPLEE'! To 100 cc. portions of an aviation gasoline (containing 2 cc. tetraethyl lead, 0.9 ethylenedibromide and 0.098 gram of N,N'-di(secondary butyl) -p-phenylenediamine per gallon of gasoline) were added organic nitrogenous bases in the proportion of 0.0032% by weight based on the fuel or about 89% by weight based on the N,N'-

Table III Base Period Dodecylamine Stearylamine. Diisopropylsmine Di-n-butylamine Benzylamine alpha-Pipecoline Tetrabutyl ethylenediamine Phenylethylaminc EXAMPLES A sample of iso-octane (containing 4.6 cc. tetraethyl lead, 2.07 cc. ethylenedibromide, 0.0075 gram of a blue gasoline dye and 0.098 gram N-',N'- di(secondary butyl) -p-phenylenediamine per'gallon of iso-octane) changed from blue to purple in 1 minute when exposed to direct sunlight. Another sample of the same fuel was treated with 0.0012% by weight of n-butylamine, corresponding to 33.3% by weight based on the N,N-di(secondary butyl) -p-phenylenediamine and a mol ratio of 1.007 to 1. The treated sample remained blue on exposure to direct sunlight for 120 minutes. v

EXAMPLE 7 A sample of iso-octane (containing 0.5 cc. tetraethyl lead, 0.225 cc. ethylenedibromide, 0.0075 gram of ablue gasoline dye and 0.098 gram N,N'-di(secondary butyl) -p-phenylenediamine per gallon of iso-octane) changed from blue to purple in 2.5 minutes when exposed to direct sunlight. Another sample of the same fuel was treated with 0.0012% by weight of n-butylamine, corresponding to 33.3% by weight based on the N,N'-di(secondary butyl) -p-phenylenediamine and a incl Fatioof 1.007 to 1. The treated sample remained blue on exposure to direct sunlight for 120 minutes.

EXAMPLE 8 A sample of iso-octane (containing 4.6- cc.

tetraethyl lead, 2.07 cc. ethylenedibromide, 0.0075

gram of a blue gasoline dye and 0.049 gram N,N'- di(secondary butyl) p phenylenediamine per gallon of iso-octane) changed from blue to purple in 5 minutes when exposed to direct sunlight. Another sample of the same fuel was treated with 0.0006% by weight of n-butylamine, corresponding to 33.3% by weight based on the N,N'-di(secondary butyl) -p-phenylenediamine and a mol ratio of 1.007 to 1. The treated sample remained blue on exposure to direct sunlight for 120 minutes.

EXAMPLE 9 A gallon of iso-octane (containing 2 cc. tetraethyl lead, 0.9 cc. ethylenedibromide and 0.098 gram N,N'-di(secondary butyl)-p-phenylenediamine) was divided into 100 cc. portions which were placed in clear glass sample bottles. To two of the samples was added 0.001% and 0.002% by weight, respectively, of N -normal-butyl-p-aminophenol, corresponding to 27.8% and 55.6% by weight, respectively, based on the N,N'-di(secondary butyl)-p-phenylenediamine and mol ratios of 0.372 and 0.744, respectively, to 1. These samples were placed in direct sunlight along with a control sample of the same fuel to which no N-normal-butyl-p-aminophenol had been added. The control sample turned distinctly pink within 0.5 minute and the samples containing 0.001% and 0.002% of N-normal-butyl-p-aminophenol, turned pink in 0.75 minute and 1.0 minute. respectively.

When samples of the fuel of Example 9 were treated with 0.072% by weight of aniline, 0.0032% by weight of monomethylaniline, 0.0032% by weight of alpha-picoline, 0.001% by weight of quinoline, 0.072% by weight of pyridine and 0.072% by weight of N-methylpyrrole, re-

spectively, it was found that neither aniline nor N-methylpyrrole had any apparent effect to prevent or retard the color formation while the others gave results on the order of those obtained with N normal-butyl-p-aminophenol. Dissociation constants K for representative amines of this group are; for aniline,

alpha-picoline,

pyridine, K=2.3 10- and quinoline,

Example 9 and the paragraph which follows it are included for comparative purposes and show that the dissociation constants and other limitations on the organic nitrogenous bases, to be used in accordance with our invention, are

from the spirit or scope of our invention. It will be particularly understood that mixtures of any two or more of such organic nitrogenous bases may be employed in place of any single such base.

It is well lmown that gum inhibitors in cracked gasoline tend to slowly deteriorate and form colored products which, however, become objectionable only after several days or weeks. Such deterioration is generally recognized to be an oxidation reaction and it has been found that various amines will inhibit such reaction.

I N,Nf di(secondary butyl)-p-phenylenediamine and ethylenedibromide in the presence of sunlight. Furthermore, the organic nitrogenous bases of our invention are relatively ineffective to inhibit the oxidative deterioration of N,N'- di(secondary butyl)-p-phenylenediamine and similar gum inhibitors. Accordingly, it is apparent that we are dealing with an entirely different problem involving a completely different reaction than the inhibition of oxidative deterioration of gum inhibitors. It is thus apparent that, by our invention, we have effectively solved a serious problem in the art in a novel manner and that our invention constitutes a new and valuable contribution to the art.

We claim:

1. A motor fuel consisting essentially of saturated hydrocarbon aviation fuel, from about 0.5 cc. to about 8 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.22 cc. to about 3.6 cc. of ethylenedibromide per gallon of aviation fuel, from about 0.0014% to about 0.008% by weight of N,N' di(secondary butyl) -p-phenylenediamine and from about 0.25 mol to about 3 mols of an organic nitrogenous base for each mol of N,N di(secondarybutyl) -p-phenylenediamine, the organic nitrogenous base being composed solely of carbon atoms, hydrogen atoms and at least one basic nitrogen atom and having a dissociation constant of from about 2x 10 to about 1 l0" and boiling above C. and being free of multiple bonds other than those of a benzene ring.

2. A motor fuel consisting essentially of saturated hydrocarbon aviation fuel, from about 0.5

di(secondary butyl) p phenylenediamirie and .from about 0.5 mols to about 3 mols of a saturated 4. A motor fuel consisting essentially of saturated hydrocarbon aviation fuel, from about 0.5 cc. to about 8 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.22 cc. to about 3.6 cc. of ethylenedibromide per gallon of aviation fuel, from about 0.0014% to about 0.008% by weight of N,N'-di(secon dary butyl) pphenylenediamine and from about 0.5 mol to about 3 mols of isopropylamine for each mol of N,N-di(secondary butyl) -p-phenylenediarnine.

5. A motor fuel consisting essentially of saturated hydrocarbon aviation fuel, from about 0.5 cc. to about 8 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.22 cc. to about 3.6 cc.

I of ethylene dibromide per gallon of aviation fuel,

cc. to about 8 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.22 cc. to about 3.6 cc. of ethylenedibromide per gallon of aviation fuel, from about 0.001% to about 0.008% by weight of N,N'-di(secondary butyl-p-phenylenediamine and from about 0.25 mol to about 3 mols of a saturated organic nitrogenous base for each mol of N,N-di(secondary butyl)-p-phenylenediamine, the organic nitrogenous base being composed solely of carbon atoms, hydrogen from about 0.0014% to about 0.008% by weight of N,N'-di(secondary butyl)-p-phenylenediamine and from about 0.5 mol to about 3 mols of piperidine for each mol of N,N'-di(secondary butyl)- p-phenylenediamine,

6. A motor fuel consisting essentially of saturated hydrocarbon aviation fuel, from about 0.5 cc. to about 8 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.22 cc. to about 3.6 cc. of ethylenedibromide per gallon of aviation fuel, from about 0.0014% to about 0.008% by weight of N,N-di(secondary butyl) -p-phenylenediamine and from about 0.25 mol to about 2 mols of a saturated organic nitrogenous base for each mol of N,N'-di (secondary butyl) -p-phenylenediamine, the organic nitrogenous base being composed solely of carbon atoms, hydrogen atoms and a plurality of basic nitrogen atoms and having a dissociation constant of from about 2X 10- to about 1 X 10* and boiling above 30 C.

'7. A motor fuel consisting essentially of saturated hydrocarbon aviation fuel, from about 0.5

cc. to about 8 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.22 cc. to about 3.6 cc. of ethylenedibromide per gallon of aviation fuel, from about 0.0014% to about 0.008% by weight of N,N-di(secondary butyl) -p-phenylenediamine and from about 0.25 mol to about 2 mols of diethylenetriamine for each mol of N,N-di(secorganic nitrogenous base for each mol of N,N'-

di(secondary butyl) -p'-phe'nylenediamine, the organic nitrogenous base being composed solely of carbon atoms, hydrogen atoms, and at least one basic nitrogen atom and having a dissociation constant of from about 2X 10- to about 1Xl0- and boiling above 30 C. and being free of multiple bonds other than those of a benzene ring.

9. A motor fuel consisting essentially of saturated hydrocarbon aviation fuel, from about 2 cc. to about 5 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.9 cc. to about 2.25 cc. of ethylenedibromide per gallon of aviation fuel,

'l-l from about, o.oo,1a ,;t about 0.004 by weight of N,N"-di(second ary butyl) -p-phenylenediamine and an organic nitrogenous base composed solely of carbon atoms, hydrogen atoms and at least one basic nitrogen atom which has a dissociation constant of from about 2 10- to about 1x10 and boils above 30 C. and is free of multiple bonds other than those of a benzene ring, the organic nitrogenous base when it contains a single basic nitrogen atom being present in a proportion of o about 0.25 to about 2 mols for each mol of N,N'- l5 di(secondary butyl) -p-phenylenediamine.

10. A motor fuel consisting essentially of saturated hydrocarbon aviation fuel, from about 2 cc. to about 5 cc. of tetraethyl lead per' gallon of aviation fuel, fromabout 0.9 cc. to about 2.25 cc.

of ethylenedibromide per gallon of aviation fuel, from about 0.0018% to about 0.004% by weight of N,N'-di(secondary butyl) -p-phenylenediamlne and a saturated organic nitrogenous base composed solely'of carbon atoms, hydrogen atoms and at least one basic nitrogen atom which has a dissociation constant of from about 2X 10- to about 1x 10- and boils above C., the organic nitrogenous base when it contains a single basic nitrogen atom being present in a proportion of 30 from about -0.6 to about 2.5 mols for each mol of N,N-di(secondary butyl) -p-phenylenediamine and when it contains a plurality of basic nitrogen atoms being present in a proportion of from about 0.3 to about 1.7 mols for each mol of N,N'-

di(secondary butyl) -p-phenylenediamine.

11. A motor fuel consisting essentially of saturated hydrocarbon aviation fuel, from about 2 cc. to about 5 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.9 cc. to about 2.25 cc. of 40 ethyleneclibromide per gallon of aviation fuel, from about 0.0018% to about 0.004% by weight of N,N'-di(secondary butyl) p phenylenediamine and from about 0.6 mol to about 2.5 mols of an organic nitrogenous base for each mol of N,N'-

di(secondary butyl) -p-phenylenediamine, the organic nitrogenous base being composed solely of carbon atoms, hydrogen atoms and a single basic nitrogen atom andhaving a dissociation constant to about 5 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.9 cc. to about 2.25 cc. of ethylenedibromide per gallon of aviation fuel, from about 0.0018% to about 0.004% by weight of N,N'-di'(secondary butyl) p phenylenediamine and from about 0.6 mol to about 2.5 mols of a saturated organic nitrogenous base for each mol of N,N' di(secondary butyl) p phenylenediamine, the organic nitrogenous base being composed solely of carbon atoms, hydrogen atoms anda single basic nitrogen atom and having a disso- 08 ciation constant of from about 2 10'- to about 1 10 and boiling above C.

. i2 13. A motor fuel consisting essentially of saturated hydrocarbon aviation fuel, from about 2 cc.

' to about 5 cc. of tetraethyl leadper gallon of aviationfuel, from about 0.9 cc. to about 2.25 ,cc. of ethylenedibromide per gallon of aviation fuel, from about 0.0018% to about 0.004% by weight of N,N -.di (secondary butyl) p phenylenediamine and from about 0.6 mol to about 2.5 mols of isopropylamine for each mol of N,N'-di(secondary butyl) -p-phenylenediamine.

14. A motor fuel consisting essentially of saturated hydrocarbon aviation iuel, from about 2 cc. to about5 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.9 cc. to about 2.25 cc. of ethylenedibromide per gallon of aviation fuel, from about 0.0018% to about 0.004% by weight of N,N'-di(secondary butyl) p phenylenediamine and from about 0.6 mol to about 2.5 mols of piperidine' for each mol of N,N'-di(secondary butyl) -p-phenylenediamine.

15. A motor fuel consisting essentially of saturated hydrocarbon aviation fuel, from about 2 cc.

to about 5 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.9 cc. to about 2.25 cc. of ethylenedibromide per gallon of aviation fuel, from about 0.0018% to about 0.004% by weight of N,N-di(secondary butyl) p phenyienediamine and from about 0.3 mol to about-1.7 mols of an organic nitrogenous base for each mol of N,N- di(secondary butyl) -p-phenylenediarnine, the organic nitrogenous base being composed solely of carbon atoms, hydrogen atoms and a plurality of basic nitrogen atoms and having a dissociation constant of from about 2 10 to about 1X10- and boiling above 30 C. and being free of multiple bonds other than those of a benzene ring.

16. A motor fuel consisting essentially of'saturated hydrocarbon aviation fuel, from about 2' cc. to about 5 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.9 cc. to about 2.25 cc. of ethylenedibromide per gallon of aviation fuel, from about 0.0018% to about 0.004% by weight of N,N'-di(secondary butyl) p phenylenediamine and from 0.3 mol to about 1.7 mols of asaturated organic nitrogenous base for each mol of N,N'- di(secondary butyl) -p-phenylenediamine, the organic nitrogenous base being composed solely of carbon atoms, hydrogen atoms and a plurality of basic. nitrogen atoms and having a dissociation of from about 2 X 10- to about 1 x 10- and boiling 50 constant of from about 2X10 to about 1 l0- and boiling above 30 0.

1'7. A motor fuel consisting essentially of saturated hydrocarbon aviation fuel, from about 2 cc. to about 5 cc. of tetraethyl lead per gallon of aviation fuel, from about 0.9 cc. to about 2.25 cc..of ethylenedibromide per gallon of aviation fuel, from about 0.0018% to about 0.004% by weight of N,N'-di(secondary butyl) p phe'nylenediamine and from about 0.3 mol to about 1.? mols of diethylenetriamine for each mol of N,N-di(secondary butyl) -p-phenylenediamine.

CHARLES B. BISWELL. GEORGE ALVIN SAYERS.

No references cited. 

1. A MOTOR FUEL CONSISTING ESSENTIALLY OF SATURATED HYDROCARBON AVIATION FUEL, FROM ABOUT 0.5 CC. TO ABOUT 8 CC. OF TETRAETHYL LEAD PER GALLON OF AVIATION FUEL, FROM ABOUT 0.22 CC. TO ABOUT 3.6 CC. OF ETHYLENEDIBROMIDE PER GALLON OF AVIATION FUEL, FROM ABOUT 0.0014% TO ABOUT 0.008% BY WEIGHT OF N,N'' - DI(SECONDARY BUTYL)-P-PHENYLENEDIAMINE AND FROM ABOUT 0.25 MOL TO ABOUT 3 MOLS OF AN ORGANIC NITROGENOUS BASE FOR EACH MOL OF N,N'' - DI(SECONDARY BUTYL)-P-PHENYLENEDIAMINE, THE ORGANIC NITROGENOUS BASE BEING COMPOSED SOLELY OF CARBON ATOMS, HYDROGEN ATOMS AND AT LEAST ONE BASIC NITROGEN ATOM AND HAVING A DISSOCIATION CONSTANT OF FROM ABOUT 2X10**-3 TO ABOUT 1X10**-7 AND BOILING ABOVE 30*C. AND BEING FREE OF MULTIPLE BONDS OTHER THAN THOSE OF A BENZENE RING. 